JP7251222B2 - Motor control device and motor control method - Google Patents

Description

The present disclosure relates to control of electric motors that drive wheels.

A technology is known that includes a microcontroller as a control unit that controls an actuator provided in a vehicle, and a microcontroller monitoring unit that monitors the occurrence of an abnormality in the microcontroller, and executes fail-safe when an abnormality occurs inside the microcontroller. (For example, Patent Document 1). In recent years, a technique (so-called in-wheel motor) has been proposed in which electric motors as actuators are arranged on left and right wheels of a vehicle, and the electric motors drive the left and right wheels. Moreover, in such a technique, two control circuits may be used as control units for controlling the two left and right electric motors, respectively.

JP 2016-147585 A

In a configuration that includes two electric motors that respectively drive two left and right wheels and two control circuits that control each electric motor, if one of the two control circuits fails, the running stability of the vehicle is impaired. There is a risk. For example, a normal control circuit instructs the controlled motor to drive forward torque, and a faulty control circuit instructs the controlled motor to reverse torque, causing the vehicle to spin. Running stability may be impaired. However, in the past, the fact is that sufficient consideration has not been given to how to deal with a failure in one of the control circuits, and to fail-safe. For this reason, in a configuration comprising two electric motors for driving two left and right wheels, respectively, and two control circuits for controlling each electric motor, it is possible to prevent deterioration of running stability when one of the control circuits fails. Suppressible technology is desired.

The present disclosure can be implemented as the following forms.

As one form of the present disclosure, an electric motor control device ( 10) is provided. This electric motor control device includes a target torque instruction section (15) for instructing target torques to a right control circuit (21R) for controlling the right electric motor and a left control circuit (21L) for controlling the left electric motor, respectively; a failure occurrence specifying unit (16) for specifying whether or not a failure has occurred in the right control circuit and the left control circuit, wherein the target torque indicating unit detects a failure in one of the right control circuit and the left control circuit. When it is specified that there is a failure, the right control circuit and the left control circuit are set as a target torque for the failure specific control circuit for which the occurrence of the failure has been specified, out of the right control circuit and the left control circuit. Normal control in which failure occurrence is not specified in either the right control circuit or the left control circuit by instructing a fail-safe torque lower than a normal target torque that is a target torque in a normal state in which failure occurrence is not specified for any of the circuits. A steering angle specifying unit (14) for specifying a steering angle of the vehicle by instructing a failure target torque that is lower than the normal target torque and higher than the fail-safe torque to the circuit, In addition, the target torque instructing section instructs the normal control circuit, as the fault-time target torque, a smaller torque than when the specified steering angle is small when the specified steering angle is large.

According to the distance measuring device of this form, when the occurrence of a failure in one of the control circuits is identified, the failure identification control circuit is instructed to use a fail-safe torque lower than the normal target torque. It is possible to suppress the wheels controlled by the control circuit from generating a large torque, thereby suppressing deterioration in running stability of the vehicle. In addition, since a failure target torque that is lower than the normal target torque and higher than the fail-safe torque is instructed to the normal control circuit, the difference between the output torques of the left and right wheels increases and the running stability is improved. can be suppressed.

The present disclosure can also be implemented in various forms other than the motor control device. For example, it can be realized in the form of a vehicle including a motor control device, a computer program for realizing a motor control method, a storage medium storing such a computer program, or the like.

1 is an explanatory diagram showing a schematic configuration of a vehicle equipped with an electric motor control device as an embodiment of the present disclosure; FIG. 2 is a block diagram showing functional configurations of a motor control device and a control circuit; FIG. FIG. 4 is an explanatory diagram showing an example of setting contents of a torque map; FIG. 4 is an explanatory diagram showing a torque distribution ratio determination map; 4 is a flowchart showing a procedure of motor control processing; FIG. 5 is an explanatory diagram showing an example of setting contents of a torque reduction rate map in the first embodiment; FIG. 9 is an explanatory diagram showing an example of setting contents of a torque reduction rate map in the second embodiment; FIG. 11 is an explanatory diagram showing an example of setting contents of a torque reduction rate map in the third embodiment;

A. First embodiment:
A1. Device configuration:
As shown in FIG. 1 , the electric motor control device 10 of this embodiment is mounted on a vehicle 200 and controls the operation of a pair of front wheels 201 and 202 that constitute driving wheels of the vehicle 200 . The vehicle 200 is a four-wheeled vehicle comprising the pair of front wheels 201 and 202 and the pair of rear wheels 203 and 204 as driven wheels, and two electric motors driven by power supply from a battery (not shown) mounted thereon. 20R and 20L are used as drive sources. The electric motor 20R is attached to the front wheel 201, and the electric motor 20L is a so-called in-wheel motor attached to the front wheel 202.

In addition to the electric motor control device 10, the pair of front wheels 201 and 202, the pair of rear wheels 203 and 204, and the two electric motors 20R and 20L, the vehicle 200 includes a brake control device 120 and four brake devices 31. , 32, 33, 34, an EPS (Electronic Power Steering) control device 110, an EPS actuator 111, two control circuits 21R, 21L, a steering wheel 210, a steering gear 211, an accelerator opening sensor 41, a steering A sensor 42 , a range sensor 43 and a vehicle speed sensor 44 are provided. The electric motor control device 10, the EPS control device 110, the two control circuits 21R and 21L, and the brake control device 120 are configured to communicate with each other via an in-vehicle network 220. FIG. As the in-vehicle network 220, for example, any type of network such as CAN (Controller Area Network), LIN (Local Interconnect Network), and Ethernet (registered trademark) may be used.

The brake control device 120 controls the operation of the four brake devices 31-34. In this embodiment, the brake control device 120 is configured by an ECU (Electronic Control Unit) including a CPU, a ROM, and a RAM. The braking device 31 implements braking of the front wheels 201 . The brake device 31 has a brake rotor, a brake pad, a hydraulic actuator for operating the brake pad, and the like, and realizes braking of the front wheels 201 according to a command from the brake control device 120 . Similarly, the braking device 32 provides braking of the front wheels 202, the braking device 33 provides braking of the rear wheels 203, and the braking device 34 provides braking of the rear wheels 204, respectively.

An EPS (Electronic Power Steering) controller 110 controls the operation of an EPS actuator 111 . In this embodiment, the EPS control device 110 is configured by an ECU. EPS control device 110 implements so-called electric power steering. The EPS actuator 111 has fluid (oil), an oil pump for flowing the fluid, and the like, and generates hydraulic pressure according to a command from the EPS control device 110 to assist the operation of the steering wheel 210 .

The control circuit 21R is arranged corresponding to the front wheel 201 and controls the operation of the electric motor 20R. The electric motor 20R is a three-phase AC motor, and the control circuit 21R is a driver IC having an inverter that converts DC power supplied from a battery (not shown) into AC power, and a switching element that duty-controls the voltage supplied to the inverter. (Integrated Circuit) (driver IC 22R described later). The control circuit 21L is arranged corresponding to the front wheel 202 and controls the operation of the electric motor 20L. Like the electric motor 20R, the electric motor 20L also includes a driver IC (driver IC 22L, which will be described later). A detailed configuration of the control circuits 21R and 21L will be described later.

A steering gear 211 transmits movement of the steering wheel 210 to a pair of front wheels 201,202. The accelerator opening sensor 41 detects the amount of depression of an accelerator pedal (not shown) of the vehicle 200 as the accelerator opening, that is, the rotation angle of the motor for opening and closing the throttle valve. Steering sensor 42 is electrically connected to EPS actuator 111 by a dedicated cable, and detects the steering angle of vehicle 200 by steering wheel 210 using a signal output according to the operation of EPS actuator 111 . The steering sensor 42 is electrically connected to the EPS control device 110 by a dedicated cable, and notifies the EPS control device 110 of the detected steering angle. Range sensor 43 detects a shift range specified by a shift lever (not shown) of vehicle 200 . Range sensor 43 is electrically connected to motor control device 10 by a dedicated cable, and notifies motor control device 10 of the detected shift range. A vehicle speed sensor 44 detects the rotation speed of each wheel 201-204. The vehicle speed sensor 44 is electrically connected to the electric motor control device 10 by a dedicated cable. A signal indicating the vehicle speed output from the vehicle speed sensor 44 is a voltage value proportional to the wheel speed or a pulse wave indicating an interval corresponding to the wheel speed, and is sent to the electric motor control device 10 via a dedicated cable.

As shown in FIG. 2 , the electric motor control device 10 includes an accelerator opening specifying unit 11, a vehicle speed specifying unit 12, a shift range specifying unit 13, a steering angle specifying unit 14, a target torque instructing unit 15, and a monitoring unit. 16 , a comparator 17 , and a fault occurrence identification unit 18 . In this embodiment, the motor control device 10 is configured by an ECU.

The accelerator opening specifying unit 11 specifies the accelerator opening by receiving a signal indicating the accelerator opening notified from the accelerator opening sensor 41 . Vehicle speed identifying unit 12 identifies the vehicle speed of vehicle 200 by receiving a signal indicating the vehicle speed notified from vehicle speed sensor 44 . Shift range specifying unit 13 specifies the shift range by receiving a signal indicating the shift range notified from range sensor 43 . The steering angle identification unit 14 identifies the steering angle by receiving a signal indicating the steering angle notified from the steering sensor 42 .

The target torque instruction unit 15 determines the target torque and instructs the control circuits 21R and 21L. The target torque instruction section 15 includes an overall torque calculation section 151 and a torque distribution section 152 .

The overall torque calculator 151 calculates a target torque that the two electric motors 20R and 20L should output as a whole. Specifically, the total torque calculation unit 151 calculates the accelerator opening specified by the accelerator opening specifying unit 11, the vehicle speed specified by the vehicle speed specifying unit 12, and the shift range specified by the shift range specifying unit 13. , the target torque is calculated with reference to the torque map shown in FIG. This torque map is a map in which accelerator opening and target torque are associated with each vehicle speed. As the magnitude (absolute value) of the target torque, a larger value is set as the accelerator opening increases. A positive target torque means that the shift range is the drive (D) range, and a negative target torque means that the shift range is the reverse (R) range. Although FIG. 3 shows only three maps when the vehicle speed V is v1, v2, and v3, four or more maps are prepared in advance in this embodiment.

A torque distribution unit 152 shown in FIG. 2 determines a distribution ratio for distributing the torque calculated by the total torque calculation unit 151 to the left and right electric motors 20R and 20L, and calculates a target torque according to the determined distribution ratio. The indicated signal is notified to the two control circuits 21R and 21L, respectively, and is output to the comparator 17 as well. The target torque distribution ratio is determined based on the vehicle speed specified by the vehicle speed specifying unit 12 and the steering angle specified by the steering angle specifying unit 14 using a torque distribution ratio determination map shown in FIG. This torque distribution ratio determination map is a map in which the steering angle and the torque distribution ratio are associated with each vehicle speed. In FIG. 4, the target torque of the electric motor 20L is indicated by a thick solid line L1, and the target torque of the electric motor 20R is indicated by a thin solid line L2. For example, when the steering angle is 0°, that is, when the vehicle 200 is traveling straight, the distribution ratio is set so that the target torque of the electric motor 20L and the target torque of the electric motor 20R are 1:1. Further, for example, when the steering angle is a certain angle when turning to the right, the target torque of the electric motor 20L and the target torque of the electric motor 20R are 1:0.5, that is, the distribution ratio is 2:1. is defined. This is because, when turning to the right, it is necessary to output a larger torque from the electric motor 20L than from the electric motor 20R and to rotate the front wheels 202 at a higher speed than the front wheels 201 . Although FIG. 4 shows only three maps when the vehicle speed V is v1, v2, and v3, four or more maps are prepared in advance in this embodiment.

A monitoring unit 16 shown in FIG. 2 monitors failure of the target torque instruction unit 15 . If the target torque instruction unit 15 fails, there is a risk that an erroneous target torque value or an erroneous distribution ratio may be calculated as the target torque to be output by the two electric motors 20R and 20L as a whole. Therefore, in the electric motor control device 10 of the present embodiment, the monitoring unit 16 is provided to monitor whether or not the target torque instruction unit 15 has failed. The monitoring unit 16 has the same configuration as the target torque instruction unit 15, and determines the target torque to be output by the two electric motors 20R and 20L as a whole and the distribution ratio when distributing the torque to the left and right electric motors 20R and 20L. , outputs to the comparator 17 a signal indicating the target torque corresponding to the determined distribution ratio.

The comparator 17 receives signals indicating the target torque from the target torque instruction unit 15 and the monitoring unit 16, compares the target torques indicated by these two signals, and outputs the comparison result, that is, the difference between the target torques, to the failure occurrence identification unit. Notify 18.

The failure occurrence identification unit 18 identifies occurrence of failures in the target torque instruction unit 15 and the two control circuits 21R and 21L. Specifically, the failure occurrence identification unit 18 identifies occurrence of a failure in the target torque instruction unit 15 when the target torque difference received from the comparator 17 is equal to or greater than a predetermined threshold. When the shift range is reverse (R), the occurrence of failure may be specified when the magnitude (absolute value) of the target torque output from the target torque instruction unit 15 is equal to or greater than a predetermined threshold. good. Further, when receiving a signal indicating the occurrence of a failure (hereinafter referred to as a "failure occurrence signal") from the two control circuits 21R and 21L, the failure occurrence identification unit 18 detects at least one of the two control circuits 21R and 21L. Identify the occurrence of one failure. When the failure occurrence identification unit 18 identifies the failure occurrence as described above, the failure occurrence identification unit 18 notifies the target torque instruction unit 15 and the monitoring unit 16 of a signal indicating that the failure has occurred. In the electric motor control process to be described later, the target torque instruction unit 15 and the monitoring unit 16 that have received the notification of the occurrence of a failure generate a torque that differs from the normal target torque (normal target torque to be described later) when there is no failure, that is, A torque different from the target torque determined as described above is notified to the two control circuits 21R and 21L as the target torque.

The control circuit 21R shown in FIG. 2 includes a driver IC 22R, an actual torque calculator 23R, a comparator 24R, and an operation monitor 25R. The driver IC 22R supplies drive voltage to the electric motor 20R according to the target torque notified from the torque distribution section 152. FIG. The actual torque calculation unit 23R detects the current value of the current flowing through the electric motor 20R and the rotation speed of the electric motor 20R, and based on these current values and rotation speed, the torque actually output by the electric motor 20R (hereinafter, "actual torque") is calculated. ) is calculated. The target torque value notified from the torque distribution unit 152 and the actual torque value calculated by the actual torque calculation unit 23R are input to the comparator 24R. The comparator 24R compares these two input torque values and outputs the comparison result, that is, the torque difference, to the operation monitoring section 25R. The operation monitoring unit 25R identifies the operation of the driver IC 22R. Specifically, when the comparison result input from the comparator 24R is equal to or greater than a predetermined threshold value, the operation monitoring unit 25R identifies a failure in the driver IC 22R and outputs a failure occurrence signal to the motor control device 10 (failure occurrence identification unit 18). ). If the comparison result is less than the threshold, the driver IC 22R is operating normally, and the operation monitoring section 25R does not output the failure occurrence signal.

The control circuit 21L has a configuration similar to that of the control circuit 21R. That is, it includes a driver IC 22L, an actual torque calculator 23L, a comparator 24L, and an operation monitor 25L. The operation monitoring unit 25L identifies a failure in the driver IC 22L and notifies a failure occurrence signal to the motor control device 10 (failure occurrence specifying unit 18) when the comparison result input from the comparator 24L is equal to or greater than a predetermined threshold.

A2. Motor control processing:
The electric motor control process shown in FIG. 5 is executed when the start button of vehicle 200 is pressed to turn on electric motor control device 10 . The electric motor control process is a process for controlling the two electric motors 20R and 20L, and particularly means a fail-safe process for safely dealing with failures of the two electric motors 20R and 20L.

The fault occurrence identification unit 18 identifies whether or not a fault has occurred in the two control circuits 21R and 21L (step S105). Specifically, the fault occurrence identification unit 18 identifies whether or not a fault has occurred in the two control circuits 21R and 21L by identifying whether or not a fault occurrence signal has been received from the two control circuits 21R and 21L.

The fault occurrence identifying unit 18 determines whether or not only one of the control circuits has a fault based on the result of the identification in step S105 (step S110). If it is determined that only one of the control circuits has a failure (step S110: YES), the failure occurrence identification unit 18 notifies the target torque instruction unit 15 and the monitor that only one of the control circuits has a failure. 16, and the target torque instructing unit 15 instructs the control circuit in which the failure has been identified (hereinafter referred to as "failure-identifying control circuit") to be the fail-safe torque Tfs as the target torque. is not specified (hereinafter referred to as "normal control circuit"), the failure target torque Tfo is instructed as the target torque (step S115). The fail-safe torque Tfs is set as a predetermined value. In this embodiment, the fail-safe torque Tfs is zero. It is not limited to zero, and may be set to any value smaller than the failure target torque Tfo.

The failure target torque Tfo will be described with reference to FIG. The target torque instruction unit 15 specifies the torque reduction rate by referring to a torque reduction rate map preset in the electric motor control device 10 based on the vehicle speed and the steering angle. Then, the target torque instruction unit 15 provides a target torque to be instructed to the control circuit when no failure has occurred, that is, a target torque determined based on the specified accelerator opening, vehicle speed, and shift range (hereinafter referred to as (referred to as "normal target torque") is multiplied by the specified torque reduction rate to calculate the failure target torque Tfo.

The torque reduction rate map shown in FIG. 6 is a map in which the steering angle and the torque reduction rate are associated with each vehicle speed. In FIG. 6, the horizontal axis indicates the absolute value of the steering angle, and the vertical axis indicates the torque reduction rate. When the vehicle speed V is v1, the torque reduction rate is 0.5 when the steering angle is zero. is set as In the torque reduction rate map Ltn when the vehicle speed V is vn larger than v1, the torque reduction rate when the steering angle is zero is the same as the torque reduction rate map Lt1 and is set to 0.5. Further, in this torque reduction rate map Ltn, as in the torque reduction rate map Lt1, it is set such that the larger the absolute value of the steering angle, the smaller it gradually becomes. For ease of comparison, the torque reduction rate map Lt1 is indicated by a dashed line in the torque reduction rate map Ltn when the vehicle speed V is vn.

As can be understood by comparing the solid-line torque reduction rate map Ltn and the broken-line torque reduction rate map Lt1 in FIG. 6, in the present embodiment, when the absolute value of the steering angle is the same, the higher the vehicle speed, A small value is set as the torque reduction rate. Therefore, when the absolute value of the steering angle is the same, the higher the vehicle speed, the smaller the target torque commanded to the normal control circuit. Thus, in the present embodiment, the greater the absolute value of the steering angle and the greater the vehicle speed, the smaller the torque reduction rate, and a smaller torque is indicated as the failure target torque Tfo. If only one control circuit fails, the fail-safe torque Tfs becomes zero, so the output of the motor corresponding to the failure specific control circuit becomes zero, and only the motor corresponding to the normal control circuit operates to drive the wheels. will let you In such a situation, when the steering angle is large, that is, when the vehicle 200 travels around a curve, only one wheel rotates, so the operation of the vehicle 200 becomes unstable. Therefore, in this case, the electric motor control device 10 of the present embodiment sets a small value as the target torque to be instructed to the normal control circuit, and rotates the wheels slowly, thereby suppressing deterioration of running stability. I have to. In addition, the higher the vehicle speed, the lower the stability when running on one wheel. Therefore, in this case as well, the electric motor control device 10 of the present embodiment sets a small value as the target torque to be instructed to the normal control circuit, and the wheels are rotated. He is trying to suppress that running stability falls by making it rotate slowly.

As shown in FIG. 6, even when the steering angle is zero, that is, when the vehicle 200 travels straight, the torque reduction rate is set to 0.5, and the target torque is half the normal target torque. When one of the control circuits fails and only one of the drive wheels is driven, the control circuit is instructed to output a smaller torque than during normal operation, thereby improving the running stability of the vehicle 200 when traveling straight. This is for suppressing a decrease in

As shown in FIG. 5, when it is determined in step S110 that only one of the control circuits is not malfunctioning (step S110: NO), the failure occurrence identifying unit 18 determines that both control circuits are malfunctioning. (step S120). If it is determined that both control circuits are out of order (step S120: YES), the target torque instructing unit 15 instructs the fail-safe torque as the target torque to both of the two control circuits 21R and 21L. (step S125). On the other hand, if it is determined that both control circuits are not malfunctioning, that is, if it is determined that neither of the two control circuits 21R, 21L is malfunctioning (step S120: NO), the target The torque instructing unit 15 instructs the normal target torque as the target torque to both of the two control circuits 21R and 21L (step S130).

According to the electric motor control device 10 of the first embodiment described above, when the occurrence of a failure in one of the two control circuits 21R and 21L is identified, the normal target for the failure identification control circuit is determined. Since the fail-safe torque lower than the torque is instructed, it is possible to prevent the wheel controlled by the fault identification control circuit from generating large torque, thereby suppressing deterioration of the running stability of the vehicle. In addition, since a failure target torque that is lower than the normal target torque and higher than the fail-safe torque is instructed to the normal control circuit, the difference between the output torques of the left and right wheels increases and the running stability is improved. can be suppressed.

In addition, when the steering angle is large, the target torque instruction unit 15 instructs the normal control circuit to provide a smaller torque than when the steering angle is small as the failure target torque. Even if it is easy to do so, it is possible to suppress deterioration in running stability.

In addition, when the vehicle speed is high, the target torque instruction unit 15 instructs the normal control circuit to provide a smaller torque than when the vehicle speed is low as the failure target torque. Even so, deterioration in running stability can be suppressed.

In addition, as the failure target torque, a torque having a predetermined ratio to the normal target torque is instructed to the normal control circuit, so that the processing load for calculating the failure target torque in the motor control device 10 can be reduced. .

In addition, since the fail-safe torque is zero, it is possible to prevent the torque from being output based on an erroneous instruction from the failure identification control circuit, thereby further suppressing deterioration in running stability.

Further, when the differential torque between the output torque calculated using the current and the rotation speed of the electric motors 20R and 20L to be controlled and the target torque is larger than a predetermined threshold value, it is specified that there is a failure. However, if the differential torque is less than the threshold value, it is specified that there is no failure, so it is possible to accurately specify the presence or absence of failure.

B. Second embodiment:
Since the configuration of the electric motor control device 10 of the second embodiment is the same as that of the electric motor control device 10 of the first embodiment, the same constituent elements are denoted by the same reference numerals, and detailed description thereof will be omitted. Also, the procedure of the motor control process of the second embodiment is the same as the procedure of the motor control process of the first embodiment. The electric motor control device 10 of the second embodiment differs from the electric motor control device 10 of the first embodiment in the setting contents of the torque reduction rate map.

In the torque reduction rate map of the first embodiment, as shown in FIG. 6, the torque reduction rate is set to gradually decrease as the absolute value of the steering angle increases. On the other hand, as shown in FIG. 7, the torque reduction rate map of the second embodiment, for example, the torque reduction rate map Lt11 when the vehicle speed V is v1, increases in steps as the absolute value of the steering angle increases. It is set so that the torque reduction rate is generally small. The torque reduction rate map Lt11 is indicated by a broken line together with the torque reduction rate map Ltn1 when the vehicle speed V is vn higher than v1. Also in the second embodiment, when the absolute value of the steering angle is the same, the higher the vehicle speed, the smaller the torque reduction rate.

The electric motor control device 10 of the second embodiment described above has the same effects as the electric motor control device 10 of the first embodiment. As can be understood from the first embodiment and the second embodiment, when the specified steering angle is large, a smaller torque than when the steering angle is small is instructed to the normal control circuit as the failure target torque. Any configuration may be used for the motor control circuit of the present disclosure.

C. Third embodiment:
Since the configuration of the electric motor control device 10 of the third embodiment is the same as that of the electric motor control device 10 of the first embodiment, the same constituent elements are denoted by the same reference numerals, and detailed description thereof will be omitted. Also, the procedure of the motor control process of the third embodiment is the same as the procedure of the motor control process of the first embodiment. The electric motor control device 10 of the third embodiment differs from the electric motor control device 10 of the first embodiment in the setting contents of the torque reduction rate map.

In the torque reduction rate map of the first embodiment, as shown in FIG. 6, the torque reduction rate is set to gradually decrease as the absolute value of the steering angle increases. Also, the torque reduction rate is set to gradually decrease as the vehicle speed increases. In contrast, as shown in FIG. 8, in the torque reduction rate map Lt21 of the third embodiment, the torque reduction rate is a fixed value of 0.2 regardless of the magnitude of the steering angle and vehicle speed. Note that the fixed value is not limited to 0.2 and may be set to any value smaller than 1.

The electric motor control device 10 of the third embodiment described above has the same effects as the electric motor control device 10 of the first embodiment. That is, when a failure occurs, the normal control circuit is instructed to have a torque smaller than the normal target torque as the target torque.

D. Other embodiments:
(D1) In each embodiment, failure of the two control circuits 21R and 21L means failure of the driver ICs 22R and 22L, but the present disclosure is not limited to this. For example, it may be a failure of any component constituting the control circuits 21R and 21L, such as the actual torque calculators 23R and 23L, the comparators 24R and 24L, and the operation monitor sections 25R and 25L. For example, the two control circuits 21R and 21L are configured to periodically notify the motor control device 10 of normality, and when an abnormality is notified in such communication or when such notification does not arrive, the two control circuits 21R and 21L It may be configured to identify failures in the circuits 21R and 21L. According to such a configuration, the motor control device 10 can identify the occurrence of a failure not only in the driver ICs 22R and 22L but also in any component of the control circuits 21R and 21L.

(D2) In the first and second embodiments, when both the steering angle and the vehicle speed are large, a smaller torque is instructed to the normal control circuit as the failure target torque Tfo than when it is small. , the disclosure is not limited thereto. For only one of the steering angle and the vehicle speed, a smaller torque may be instructed to the normal control circuit as the failure target torque Tfo when the steering angle or the vehicle speed is large than when it is small.

(D3) In each embodiment, the failure target torque Tfo is calculated with reference to the torque reduction rate map, but the present disclosure is not limited to this. For example, the failure target torque Tfo may be determined by referring to a map in which the target torque (failure target torque) value is preset according to the vehicle speed, steering angle, accelerator opening and shift range. In the third embodiment, a fixed value may be set in advance as the failure target torque Tfo. Further, instead of referring to the map, the failure target torque Tfo may be determined by calculation using a preset calculation formula.

(D4) In each embodiment, when two control circuits 21R and 21L fail while the vehicle 200 is running, the failure identification control circuit is immediately supplied with the fail-safe torque, and the normal control circuit is supplied with the failure safety torque. Although the hour target torque Tfo is indicated as the target torque, the present disclosure is not limited to this. For example, when the two control circuits 21R and 21L fail while the vehicle 200 is running, first, the fail-safe torque Tfs is instructed as the target torque for both the control circuits 21R and 21L, When the vehicle 200 starts running after the vehicle 200 stops or travels at a speed equal to or lower than a predetermined speed, the failure identification control circuit is supplied with the fail-safe torque Tfs, and the normal control circuit is supplied with the failure target torque Tfo. , may be indicated as target torques.

(D5) In each embodiment, the driving wheels of the vehicle 200 were the pair of front wheels 201, 202, but instead of the pair of front wheels 201, 202, or in addition to the pair of front wheels 201, 202, , the pair of rear wheels 203, 204 may be drive wheels. In this configuration, motors are attached to the pair of rear wheels 203 and 204, respectively, and a control circuit is installed corresponding to each motor.

(D6) In each embodiment, the operation of the corresponding electric motor 20R or 20L is stopped by setting zero as the fail-safe torque Tfs for the fault identification control circuit, but the present disclosure is limited to this. not. For example, by disconnecting the relay provided in the power supply circuit connecting the failure identification control circuit and the battery to cut off the power supply from the battery to the failure identification control circuit, the corresponding electric motor 20R or 20L can be operated. You can stop it.

(D7) In each embodiment, at least one of the two electric motors 20R and 20L may be a motor generator. In such a configuration, the motor generator corresponds to a subordinate concept of the generator in the present disclosure.

(D8) The motor controller 10 and techniques thereof described in the present disclosure were provided by configuring a processor and memory programmed to perform one or more functions embodied by a computer program. It may also be implemented by a dedicated computer. Alternatively, the motor controller 10 and techniques described in this disclosure may be implemented by a dedicated computer provided by configuring the processor with one or more dedicated hardware logic circuits. Alternatively, the motor controller 10 and techniques described in this disclosure may be implemented by combining a processor and memory programmed to perform one or more functions and a processor configured by one or more hardware logic circuits. It may also be implemented by one or more dedicated computers configured in combination. The computer program may also be stored as computer-executable instructions on a computer-readable non-transitional tangible recording medium.

The present disclosure is not limited to the embodiments described above, and can be implemented in various configurations without departing from the scope of the present disclosure. For example, the technical features in each embodiment corresponding to the technical features in the form described in the outline of the invention are used to solve some or all of the above problems, or Substitutions and combinations may be made as appropriate to achieve part or all. Also, if the technical features are not described as essential in this specification, they can be deleted as appropriate.

10 electric motor control device 15 target torque instruction unit 18 failure occurrence identification unit 20R electric motor 20L electric motor 21R control circuit 21L control circuit 200 vehicle 201 wheel 202 wheel

Claims (5)

An electric motor control device (10) for controlling a right electric motor (20R) for driving right wheels (201) of a vehicle (200) and a left electric motor (20L) for driving left wheels (202) of the vehicle,
a target torque instruction unit (15) for instructing target torques to a right control circuit (21R) for controlling the right electric motor and a left control circuit (21L) for controlling the left electric motor;
a failure occurrence identification unit (18) that identifies whether or not a failure has occurred in the right control circuit and the left control circuit;
with
When it is specified that one of the right control circuit and the left control circuit has failed, the target torque instruction unit
With respect to the failure-identified control circuit of the right-side control circuit and the left-side control circuit, the occurrence of failure is not specified as the target torque for either the right-side control circuit or the left-side control circuit. instructing a fail-safe torque that is lower than the normal target torque, which is the target torque in a normal state;
A failure target torque lower than the normal target torque and higher than the fail-safe torque is instructed for a normal control circuit in which the occurrence of a failure is not specified, out of the right control circuit and the left control circuit. death,
A steering angle identification unit (14) that identifies a steering angle of the vehicle,
When the specified steering angle is large, the target torque instruction unit instructs the normal control circuit to provide a smaller torque than when the steering angle is small as the failure target torque.
motor controller. In the electric motor control device according to claim 1 ,
further comprising a vehicle speed identification unit (12) that identifies the vehicle speed of the vehicle,
When the specified vehicle speed is high, the target torque instruction unit indicates to the normal control circuit a torque smaller than when the vehicle speed is low as the failure target torque.
motor controller. In the electric motor control device according to claim 1 or claim 2 ,
wherein the fail-safe torque is zero;
motor controller. In the electric motor control device according to any one of claims 1 to 3 ,
The failure occurrence identification unit identifies occurrence of a failure in the right control circuit and the left control circuit by receiving information indicating whether or not a failure has occurred from the right control circuit and the left control circuit,
The right control circuit and the left control circuit each have an operation monitoring unit (25R, 25L),
The operation monitoring unit
Acquiring the current and the number of revolutions flowing through the controlled electric motor of the right electric motor and the left electric motor;
calculating the output torque of the controlled motor using the acquired current and rotation speed;
calculating a differential torque between the calculated output torque and the target torque indicated by the target torque indicating unit;
If the magnitude of the calculated differential torque is greater than a predetermined threshold, it is specified that there is a failure, and if it is less than the threshold, it is specified that there is no failure.
motor controller. A control method for controlling a right electric motor that drives right wheels of a vehicle and a left electric motor that drives left wheels of the vehicle using a motor control device, comprising:
identifying whether or not a failure has occurred in a right side control circuit for controlling the right side electric motor and a left side control circuit for controlling the left side electric motor in the electric motor control device;
When it is specified that one of the right side control circuit and the left side control circuit has failed in the electric motor control device,
instructing a fail-safe torque as a target torque to the failure-identifying control circuit in which the occurrence of the failure has been identified, out of the right control circuit and the left control circuit;
For a normal control circuit in which failure occurrence is not specified among the right control circuit and the left control circuit, the target torque is a normal state in which failure occurrence is not specified for both the right control circuit and the left control circuit. instructing a failure target torque that is lower than the normal target torque and higher than the fail-safe torque;
with
The step of indicating the failure target torque includes:
determining a steering angle of the vehicle;
a step of instructing the normal control circuit, as the fault-time target torque, to provide a smaller torque than when the specified steering angle is small compared to when the specified steering angle is large;
control methods , including ;

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